# US 10,312,596 B2 · Dual-polarization, circularly-polarized, surface-wave-waveguide, artificial-impedance-surface antenna

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- Number: US 10,312,596 B2
- Document ID: US10312596B2
- Status: Granted
- Kind: B2
- Application number: 14/310,895
- Filed: 2014-06-20
- Published: 2015-12-24
- Granted: 2019-06-04
- Earliest claimed: 2014-06-20
- Assignees: HRL Laboratories, LLC
- Applicants: Hrl Laboratories LLC
- Inventors: Daniel J. Gregoire
- Web page: https://patentgrep.com/patent/US10312596B2

## CPC

- H01Q 13/206: {Microstrip transmission line antennas}
- H01Q 13/20: Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave
- H01Q 13/26: Surface waveguide constituted by a single conductor, e.g. strip conductor
- H01Q 15/006: {Selective devices having photonic band gap materials or materials of which the material properties are frequency dependent, e.g. perforated substrates, high-impedance surfaces}
- H01Q 21/24: Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction {(circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001)}
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)

## Abstract

A dual-polarization, circularly-polarized artificial-impedance-surface antenna has two adjacent tensor surface-wave waveguides (SWGs), a waveguide feed coupled to each of the two SWGs and a hybrid coupler having output ports, each output port of the hybrid coupler being connected to the waveguide feeds coupled to the two SWGs, the hybrid coupler, in use, combining the signals from input ports of the 90° hybrid coupler with phase shifts at its output ports.

## Claims

### Claim 1

A dual-polarization, circularly-polarized artificial-impedance-surface antenna comprising:
(1) two adjacent tensor surface-wave waveguides (SWGs);
(2) two waveguide feeds, one of said waveguide feeds being coupled to each of the two SWGs;
(3) a hybrid coupler having output ports, each output port of the hybrid coupler being connected to one of the waveguide feeds, the hybrid coupler, in use, combining the signals from input ports of the hybrid coupler with phase shifts at its output ports.

### Claim 2 (depends on 1)

The antenna of claim 1 wherein the SWGs are disposed on a common substrate.

### Claim 3 (depends on 2)

The antenna of claim 2 wherein the SWGs polarization is rotated 90° with respect to each other and wherein the hybrid coupler is a 90° hybrid coupler.

### Claim 4 (depends on 2)

The antenna of claim 2 wherein the SWGs include metallic strips or patches disposed in an elongated array on a top surface of a dielectric sheet, the dielectric sheet having a ground plane on a bottom surface thereof.

### Claim 5 (depends on 2)

The antenna of claim 2 wherein the SWGs are elongated and each have a width which is between ⅛ to 2 wavelengths of an operational frequency of the SWGs and have a length which is between 2 and 30 wavelengths of said operational frequency of the SWGs.

### Claim 6 (depends on 5)

The antenna of claim 5 wherein each of the SWGs comprises metallic strips slanted at an angle with respect a common direction of elongation of the SWGs.

### Claim 7 (depends on 6)

The antenna of claim 6 wherein said metallic strips are disposed at 45° angle with respect to said common direction of elongation of the SWGs.

### Claim 8 (depends on 7)

The antenna of claim 7 wherein said metallic strips in one SWG are disposed at 90° angle with respect said metallic strips in the other SWG.

### Claim 9 (depends on 4)

The antenna of claim 4 wherein said metallic strips or patches are arranged in repeating patterns of varying thicknesses or sizes distributed along a length of each SWG.

### Claim 10 (depends on 1)

The antenna of claim 1 wherein the SWGs include impedance elements that are spaced with a period of 1/20 to ⅕ wavelength apart from each other along the length of the SWG.

### Claim 11 (depends on 1)

The antenna of claim 1 wherein the surface impedance tensor produces a modulated impedance pattern.

### Claim 12 (depends on 1)

The antenna of claim 1 wherein the SWGs include impedance elements that are formed by metallic patches with slices through them and wherein said slices are angled at 45° with respect to a major axis of the SWGs so as to form an impedance tensor for each SWG having a polarization which is aligned with said slices.

### Claim 13

A method of simultaneously transmitting two oppositely handed circularly polarized RF signals comprising the steps of:
i. providing a dielectric surface with a pair of elongate artificial impedance surface antennas, each of said artificial impedance surface antennas including a pattern of metallic geometric stripes or shapes disposed on said dielectric surface for guiding surface waves on said dielectric surface, the metallic geometric stripes or shapes having varying sizes which form a repeating pattern of said varying sizes, the repeating pattern of the each of said pair of elongate artificial impedance surface antennas having an angular relationship with reference to a major axis of said pair of elongate artificial impedance surface antennas, a first one of said pair of elongate artificial impedance surface antennas having a positive angular relationship to said major axis and second one of said pair of elongate artificial impedance surface antennas having a negative angular relationship to said major axis; and
ii. applying RF energy to said pair of elongate artificial impedance surface antennas, said RF energy applied to said pair of elongate artificial impedance surface antennas forms RF waves that travel as surface waves on said dielectric surface signals and leave said surface as an RF emission having different relative phases selected such that the RF emission transmitted by said pair of elongate artificial impedance surface antennas are simultaneously both left handed circularly polarized and right handed circularly polarized.

### Claim 14 (depends on 13)

The method of claim 13 wherein the repeating pattern of said varying sizes has a 45 degree angular relationship with reference to the major axis, one of the repeating patterns having a positive 45 degree angular relationship with reference to the major axis and the other one of the repeating patterns having a negative 45 degree angular relationship with reference to the major axis and wherein the phase of RF energy applied to said pair of elongate artificial impedance surface antennas has a relative 90° phase difference.

### Claim 15

A method of simultaneously receiving two oppositely handed circularly polarized RF signals comprising the steps of:
(i) sending the signals received by two SWGs into two input ports of a 3 dB 90 degree hybrid coupler, the coupler also having two output ports, the two SWGs being defined in a single sheet of printed circuit board material; and
(ii) extracting LHCP and RHCP signals from the output two ports of the hybrid coupler.

### Claim 16 (depends on 1)

The antenna of claim 1 wherein the waveguide feeds each flares from a relatively narrow portion thereof which is coupled with said hybrid coupler to a relatively wide portion thereof, the relatively wide portion of each of said waveguide feeds mating with only one of said SWGs.

### Claim 17 (depends on 16)

The antenna of claim 16 wherein each waveguide feeds flares in a curve until its width matches a width of the SWG to which it is mated.

### Claim 18 (depends on 17)

The antenna of claim 17 wherein the curve is an exponential curve.

### Claim 19

An antenna comprising:
two surface-wave waveguides (SWGs) defined in a single sheet of printed circuit board material;
two waveguide feeds defined in said single sheet of printed circuit board material, the two waveguide feeds each having
(i) a wider end which is coupled to one of the two SWGs and
(ii) a narrower end.

### Claim 20 (depends on 19)

The antenna of claim 19 wherein each of the two SWGs comprise an elongated two dimensional array of metallic elements, the metallic elements each having a length and a width, the width of the metallic elements varying along a length of the elongated array of metallic elements in a repeating pattern of width variations.

### Claim 21 (depends on 20)

The antenna of claim 20 wherein the lengths of the elongated array of metallic elements remain constant along the length of the elongated array of metallic elements.

### Claim 22 (depends on 21)

The antenna of claim 21 wherein the lengths of the metallic elements of one of the SWGs are arranged at a 45° angle to the length of the elongated array of metallic elements while the lengths of the metallic elements of the other one of the SWGs are arranged at a 90° angle to the metallic elements of the one of the SWGs.

### Claim 23 (depends on 22)

The antenna of claim 22 wherein the two waveguide feeds each flares from the narrower end thereof which is coupled with a hybrid coupler to the wider end which is coupled to one of the SWGs.

### Claim 24 (depends on 23)

The antenna of claim 23 wherein each waveguide feeds flares in a curve until its width matches a width of the SWG to which it is coupled.

### Claim 25 (depends on 24)

The antenna of claim 24 wherein the curve is an exponential curve.

### Claim 26 (depends on 1)

The antenna of claim 1 wherein the two adjacent tensor surface-wave waveguides (SWGs) have a surface impedance tensor which varies sinusoidally along a major axis thereof.

### Claim 27 (depends on 26)

The antenna of claim 26 wherein the SWGs each include metallic strips or patches disposed in an elongated array on a top surface of a dielectric sheet, the metallic strips or patches varying in size along said major axis in order to form said surface impedance tensor.

### Claim 28 (depends on 26)

The antenna of claim 26 wherein the SWGs each include metallic patches disposed in a two dimensional array of rows and columns on a top surface of a dielectric sheet, each metallic patch having a width and a height, the metallic patches in the rows of said array varying in width along said major axis in order to form said surface impedance tensor while the metallic patches in each column of said two dimensional array remaining unchanged in height.

### Claim 29 (depends on 15)

The antenna of claim 15 wherein the two phase-related ports of the hybrid coupler are phase-related to each other by ninety degrees of phase.

### Claim 30

A method of simultaneously transmitting two oppositely handed circularly polarized RF signals comprising the steps of:
(i) applying LHCP RF signals to be transmitted to a first input port of a 3 dB 90 degree hybrid coupler and applying RHCP RF signals to be transmitted to a second input port of the coupler, the coupler also having two output ports; and
(ii) coupling a signal at a first one of said output ports to one of two SWGs and coupling a signal at a second one of said output ports to the other one of two SWGs, the two SWGs being defined in a single sheet of printed circuit board material, the single sheet of printed circuit board material having a ground plane disposed at least under said two SWGs.

### Claim 31 (depends on 30)

The method of claim 30 wherein the two SWGs are polarized at 90 degrees with respect to one another.

### Claim 32 (depends on 31)

The method of claim 31 wherein the SWGs each include metallic strips or patches disposed in an elongated array on a top surface of a dielectric sheet, the method further including varying the metallic strips or patches in size along said major axis in order to form a sinusoidally varying surface impedance tensor.

### Claim 33 (depends on 31)

The method of claim 31 wherein the SWGs each include metallic patches disposed in a two dimensional array of rows and columns on a top surface of a dielectric sheet, each metallic patch having a width and a height, the method including varying a width of the metallic patches in the rows of said array along a major axis of each SWG in order to form a sinusoidally varying surface impedance tensor while the metallic patches in each column of said two dimensional array remain unchanged in height.

### Claim 34 (depends on 11)

The antenna of claim 11 wherein the modulated impedance pattern is according to
Z(x)=X+M cos(2πx/p)
where p is the period of the modulation, X is the mean impedance, and M is the modulation amplitude. X, M and p can be tuned such that the angle of the radiation θ in the x-z plane with respect to the z axis is scanned according to
θ=sin−1(n0−λ0/p)
where n0 is the mean SW index, and λ0 is the free-space wavelength of radiation and n0 is related to Z(x) by
n
0
=
1
p
⁢
∫
0
p
⁢
1
+
Z
⁡
(
x
)
2
⁢
⁢
d
⁢
⁢
x
≈
1
+
X
2
.